Re: [Bloat] [tsvwg] how much of a problem is buffer bloat today?

[Oliver Hohlfeld <oliver@net.t-labs.tu-berlin.de>]

(cross posting to bloat)

On 03/13/2013 04:28 PM, Fred Baker (fred) wrote:
> On Mar 13, 2013, at 10:23 AM, Eliot Lear <lear@cisco.com> wrote:
> 
>> I don't have an answer to that question, but Mark Allman from ICIR did
>> attempt to characterize buffer bloat on the Internet through an
>> empirical study that appeared in the January edition of CCR.  You can
>> find a reference to that paper at the following URL:
>>
>> http://www.sigcomm.org/ccr/papers/2013/January/2427036.2427041
>>
>> Eliot
> 
> Well, yes, he says that in his gigabit FTTH network he doesn't see megabit-scale problems.

Marks paper is /not/ about measuring buffer bloat in an FTTH network.
While he uses the FTTH network as /vantage point/, the paper actually
measures buffer bloat in various remote networks.

Marks paper is not the only study suggesting the extend of the problem
to be modest. The presented results are in line with recent findings by
Chirichella and Rossi [1]. Based on unpublished work, I can confirm the
low magnitude of the problem. I analyzed passive measurements of
residential users traffic from multiple continents (~60 million IPs
originating from 50\% of all ASes) and rarely find excessive RTTs that,
among other problems, can indicate the presence of buffer bloat.

In summary, bloated buffers exist and buffer bloat can be demonstrated,
but current findings suggest that it rarely occurs in practice. One
potential reason being that users do not often sustainably utilize
their uplink capacity and fill-up their potentially large queues.

Oliver

[1] To the Moon and back: are Internet bufferbloat delays really that large?
http://perso.telecom-paristech.fr/~drossi/paper/rossi13tma-a.pdf